I guess my rarely entertained interest in vore fits both categories. Like most of my kinks though, the less vanilla it gets, the more restrictions I put on it: I do like a degree of realism, and a human(oid) eating a human of the same size isn't realistic enough. So I tend to have those scenes with larger animals, but because I want my character to go in whole, it shouldn't be a very feral animal . . . Not to mention that, considering realism, I'm rarely able to play the same prey twice.
Still, I think the whole sensation of effectively extreme organic bondage is worth it if my partner happens to agree with my overly specific needs.
Another fetish I've, as far as I can recall, never been able to bring into RP, is chastity. The control, frustration and even the aesthetics of a belt or cage sound delicious, but for it to work I can only imagine a long-term RP with an erotic focus, but without any sex. I wouldn't call this an especially weird or hard kink, but rather a kink that's just a pain in the ass to do right in roleplay.